Shell: color field type (swatch picker) in tile settings and admin config

Renders <input type="color"> with the label beside it; the stored value is
always a #rrggbb string (3-digit hex widened, anything else falls back to
the schema default). Same styling in the gear popover and the admin form.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/MODULE-GUIDE.md

@@ -64,7 +64,7 @@ shell code changes, ever.
 Both schemas map field names to specs:
 
 ```
-{ "type": "string" | "number" | "boolean" | "switch" | "select" | "password" | "endpoint",
+{ "type": "string" | "number" | "boolean" | "switch" | "select" | "color" | "password" | "endpoint",
   "label": "Shown next to the field",
   "default": <value>,
   "group": "Section heading",                         // optional; see below
@@ -78,6 +78,8 @@ Both schemas map field names to specs:
 
 `boolean` renders as a checkbox; `switch` is the same true/false value shown
 as a toggle (use it for a feature on/off that other fields depend on).
+`color` renders a swatch picker and stores a `#rrggbb` string (give it a hex
+default; the tile applies it as a CSS custom property — see `pco-plan`).
 
 `group` gathers consecutive fields under a labeled subsection in the admin
 page, so a module with several distinct concerns (e.g. a ProPresenter

public/admin/admin.js

@@ -209,6 +209,17 @@ function fieldFor(key, spec, value, passwordSet, moduleId) {
     field.append(span, select);
     read = () => select.value;
     selectEl = select;
+  } else if (type === 'color') {
+    // A swatch picker; the value is always a #rrggbb string.
+    field.classList.add('color-field');
+    const span = document.createElement('span');
+    span.textContent = label;
+    const input = document.createElement('input');
+    input.type = 'color';
+    const hex = (v, fb) => (/^#[0-9a-fA-F]{6}$/.test(String(v ?? '').trim()) ? String(v).trim().toLowerCase() : fb);
+    input.value = hex(value, hex(spec?.default, '#2ee59a'));
+    field.append(span, input);
+    read = () => input.value;
   } else {
     const span = document.createElement('span');
     span.textContent = label;

public/shell.js

@@ -919,6 +919,14 @@ function unmountModule(tile) {
 
 /* ── per-tile settings popover ──────────────────────────────────────── */
 
+/** `<input type="color">` only accepts #rrggbb — anything else falls back. */
+function colorHex(value, fallback) {
+  const s = String(value ?? '').trim();
+  if (/^#[0-9a-fA-F]{6}$/.test(s)) return s.toLowerCase();
+  if (/^#[0-9a-fA-F]{3}$/.test(s)) return ('#' + s.slice(1).split('').map((c) => c + c).join('')).toLowerCase();
+  return fallback;
+}
+
 function closeSettingsPopovers() {
   document.querySelectorAll('.tile-settings').forEach((p) => p.remove());
 }
@@ -1004,6 +1012,16 @@ function toggleSettingsPopover(tile, el) {
       select.value = String(current ?? '');
       field.append(span, select);
       inputs.set(key, () => select.value);
+    } else if (type === 'color') {
+      // A swatch picker; the value is always a #rrggbb string.
+      field.classList.add('color-field');
+      const span = document.createElement('span');
+      span.textContent = label;
+      const input = document.createElement('input');
+      input.type = 'color';
+      input.value = colorHex(current, colorHex(spec?.default, '#2ee59a'));
+      field.append(span, input);
+      inputs.set(key, () => input.value);
     } else {
       const span = document.createElement('span');
       span.textContent = label;

public/style.css

@@ -626,6 +626,27 @@ body.fullscreen #grid { padding-bottom: 0; }
 }
 .field.check input { width: 15px; height: 15px; accent-color: var(--accent); }
 
+/* color fields: label on the left, swatch on the right */
+.field.color-field {
+  flex-direction: row;
+  align-items: center;
+  justify-content: space-between;
+  gap: 10px;
+  flex-wrap: wrap;
+}
+.field.color-field > span { flex: 1; min-width: 0; }
+.field.color-field input[type="color"] {
+  width: 44px;
+  height: 26px;
+  padding: 2px;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  background: var(--bg);
+  cursor: pointer;
+}
+.field.color-field input[type="color"]:focus { outline: none; border-color: var(--accent); }
+.field.color-field .field-help { flex-basis: 100%; }
+
 /* ── modal dialogs (layout name prompt etc.) ───────────────────────── */
 
 #modal-backdrop {